Power feed for rock drills



June 20, 1933. G. M. NELL POWER FEED FOR ROCK DRILLS Filed Oct. 15, 1929 4 Sheets-Sheet l INVNTOR. asfm/e 4% /V// A TTORNEY.

June 20, 1933. G NELL 1,914,815

POWER FEED FOR ROCK DRILLS Filed Oct. 15, 1929 4 Sheets-Sheet 2 INVENTOR. 3 asfove M /l e// A TTORNE Y.

June 20, 1933. G. M. NELL POWER FEED FOR ROCK DRILLS Filed Oct. 15, 1929 4 Sheets-Sheet 3 JNVENTOR. 506%0/2 W, /Ve// 4: m A TTORNEY.

June20, 1933. NE 1 ,914,815

- POWER FEED FOR ROCK DRILLS Filed Oct. 15, 1929 4 Sheets-Sheet 4 INVENTOR. Gmsval e 4% /Ve// A TTORNE Y.

Patented June 20, 1933 UNITED STATES PATN OFFQE GUSTAVE M. NELL, F DETROIT, MICHIGAN, ASSIGNOB TO CHICAGO PNEUMATIG TOOL COMEANY, OF NEV YORK, N. Y., A CORPORATION OF NE'W JERSEY POWER FEED FOR ROCK DBILLS Application filed Getober 15, 1929. Serial No. 399,726.

This invention relates to drilling machines of the percussive type and more particularly to power means for feeding or advancing such machines as the work progresses.

One object of the invention is to provide mechanism which gives a long feeding or advancing movement but which is short and compact when collapsed. Another object is to provide a power feed which can be applied to a conventional rock drill mounted upon a guide shell without material change in design of the drill or of the mounting. Another object is to arrange the feed mechanism to have an overall length no greater than the conventional shell-mounting but to give the full rangeof movement provided by the mountin Another object is to arrange tor convenient manual control of such mechanism. Still another object is to 1 permit manual braking or resistance to the power feed mechanism when the latter is in operation. Other objects will be apparent from the detailed description which follows.

In order to illustrate the invention one concrete embodiment thereof is shown in the accompanying drawings, in which:

Fig. 1 is a side'elevational view of the invention applied to a shell mounted rock drill, the feed parts being shown in section;

Fig. 2 is a top plan View of the parts shown in Fig. 1 on a much smaller scale, the drill being cut away to show the feed nut;

Fig. 3 is a right end elevational View of the parts shown in Fig. 1;

Fig. 4 is a transverse sectional View of the outer cylinder of the power teed showing, in elevation, one of the brackets for securing the cylinder to the guide shell;

Fig. 5 is an elevational view of the clamping bracket which engages the front head of the drill and is resiliently mounted on the power feed;

Fig. 6 is a longitudinal sectional view, partly broken away, showing the power feed alone and in its extended position;

Figs. 7 and 8 are fragmentary sectional views substantially on the lines 7-7 and 88, respectively, of Figs. 1 and 6, showing two views of the neutral position of the valve; and

Figs. 9 and 10, 11 and 12, and 13 and 1d are sectional views, similar to Figs. 7 and 8, showing, respectively, two views each of the re verse, forward and bleed, and forward positions of the valve.

In its essentials, the power teed comprises a plurality of nested telescoping members. The outermost member may be a cylinder 15 within which reciprocates a hollow piston 16 having ahead 16a and provided with suitable packings 161). A closure bushing 17 extends partly within the open end of cylinder 15 and is secured thereto by bolts 18 to serve as a stop for head 16a and to prevent the ejection of hollow piston 16 from cylinder 15. Members 15 and 16 cooperate to provide therebetween a variable volume annular chamber 19 of considerable extent when the parts are collapsed (Fig. 1) and which practically disappears when the parts are in the fully extended position (Fig. 6). A piston 20 havingsuitable packings 20a reciprocates within the hollow piston 16 and has a rod 20?) which projects through a stop guide bushing 21 closing the outer end of hollow piston 16. Piston 20, 20b cooperates with hollow piston 16 to form therebetween a variable volume annular chamber 22 similar to chamber 19. One or more ports 23 through hollow piston 16 near its outer end and just inwardly of annular closure bushing 21 serve to interconnect chambers 19 and 22 when power piston 16 is fully collapsed or telescoped within cylinder 15 (Fig. 1).

Movement of the telescoping members, when being extended and when being collapsed, is accomplished by fluid pressure under manual control. To this end, fluid under pressure, such as compressed air, is directed by an inlet swivel connection 24 to the bore 25 of a tapered plug valve 26 which is controlled by handle 27. From the chamber for valve 26 a passage 28 leads through the wall of cylinder 15 to a port 28a adjacent closure bushing 17, this port opening into annular chamber 19. A similar passage 29 from an axially spaced portion of the valve chamber leads to the opposite end of cylinder 15 and opens by a port 29a into chamber 30 which in diameter is the full size of the interior of cylinder 15 but varies as to axial extent with the position of the telescoping members 16 and 20, 20?). Control valve handle 27 has four positions, (a) (b) (d) (Fig. 3) corresponding respectively to neutral, reverse, forward and bleed, and forward and the connections effected by valve 26 in these positions will be presently described in setting forth the operation of the feeding means.

The feeding device heretofore described may have a variety of applications in drilling work and may be connected to a percussive drill in many ways. By preference one of the end members of the telescoping series engages a support while the other end member is secured in some manner to the drill. The accompanying drawings illustrate one arrangement to which a light and compact feed device is particularly adapted by reason of its short compass when collapsed and the great length to which it will reach when extended. As illustrated in Figs. 1, 2, and 3, the feed apparatus is applied to a percussive rock drill A of the drifter type supported upon a guide shell mounting B of conventional form. The mount provides the usual guide grooves b engaged by the slide or wing portions (6 of the drill (Fig. also a feed screw 7) rotatably supported in bearing yokes b and b at the opposite ends of the shell. Screw b has a handle 6 for manually rotating the same. Drill A has a feed nut a which engages screw 6 so that rotation of the handle 1) moves the drill back and forth on the mount as desired. To adapt the feedin g means to convenient application to mount B, the cylinder 15 is provided with laterally extending brackets 31 having aligned perforations 32 to receive the through bolts 6 (Figs. 1, 2, and which hold the parts of the shell mount B in assembled relation. Through bolts 6 extend through spacing sleeves I) which fix the position of bearing yoke 12 relative to the main body of the mount. Brackets 31 supporting cylinder are disposed at each end of spacing sleeves b (Fig. 2) and are securely clamped in place.

Suitable means are provided for attaching the other end of the feeding device, namely the projecting end of piston rod 206, to the drill. Such means may take the form of a laterally extending arm 33 having a recess shaped to it some portion of drill A such as front head 00. A cooperating semi-circular piece 34 engages the opposite side of the front head and is clamped thereagainst and secured to arm 33 as by bolts By preference the connect-ion of arm to rod is yielding so that at least a portion of the shocks incident to the operation of drill A are absorbed. To this end rod 207) is provided at its outer end with spaced. stops 36 and 37 which serve as abutments for springs 38 which engage an inwardly projecting flange 33?) on sleeve portion of arm 33 so that the same is yieldingly held in a floating position between the stops.

In order to permit eflicient operation of the power feeding apparatus, screw 5' of shell mount B is formed with a relatively steep pitch so that when rock drill A is forcibly moved, as by the power feed, nut a will cause the feed screw and its handle 5 to r0- tate clockwise or counterclockwise depending upon the direction in which the moving force is supplied to the rock drill. With this arrangement, the drill can be hand fed when the power is shut off the feeding mechanism, for starting holes, and when the feed power is on the operator can use handle 0" as a brake in controlling the feeding of drill A.

The operation of the adaptation of the invention shown in Figs. 1, 2, and 3 is as follows: \Vith the power feed collapsed, as in l igs. l and 2, and valve handle 27 in neutral position ((1 the position of the valve parts is such (Figs. 7 and 8) that motive fluid present in bore of valve 26 is shut off from both passages 28 and 29 which are open to atmosphere by grooves 39 and 40 in the valve communicating respectively with vent ports &1 and 42 in the valve case. When the operator starts the drill he manually feeds the drill forward by using handle I) to rotate feed screw Z). lVhen the drill hole is collared and he desires to use the power feed, valve handle 27 is turned through reverse position (7)) (Figs. 9 and 10) to forward and bleed position (0) (Figs. 11 and 12), the ()DQIILtOX meantime keeping a tight grip upon the handle forcibly to prevent reverse movement. As he turns valve handle 27 to positions (6) and (c), motive fluid is admitted through valve port 43 (Figs. 9 and 11) to passage 28 thereby filling annular chamber 19 and thence through port 23 filling chamber 22 (Fig. 1) when piston 16 is in fully collapsed position. At the same time the valve brings restricted port 44 into communication with passage 29 therebv filling chamber 39 at the right end of cylinder 15 with motive fluid, but some of it may escape through vent groove 40. The resulting reduced pressure is available against the full rear faces of pistons 16a and 20a and is opposed only by the relatively smaller areas of chambers 19 and 22. As the feeding mechanism starts forward, the operator moves the valve handle to forward position ((Z) Figs. 13 and 14:) thereby bringing large valve port 15 into communication with passage 29.

In the forward movement pistons 20 and 16a are extended to the limit of their outward movement and any motive fluid maintained in chambers 22 and 19, respectively, during this feeding movement makes the re 14 1s feeding uniform and under good control. Under the vibration of drill A and the forward pressure of the feed mechanism, the feed screw 7) will rotate when the operator releases feed screw handle 6 and the machine will go forward as fast as the drill steel S penetrates the rock. If the drill steel becomes stuck, the operator grasps feed screw handle 72* and prevents forward feed or forcibly reverses the same until the hole is reamed out and the steel is loosened. When ready for reverse movement, control valve 27 is thrown to reverse position (Z2) (Figs. 9 and 10) whereupon the pressure in chamber 30 is vented to atmosphere through valve groove and vent port 42 but motive fluid continues to be fed through Valve port 43 and passage 28 to valve chamber 19. This causes inward movement of hollow piston 18 until the same is fully nested within cylinder15, in which position port 23 again reestablishes communication between chambers 19 and 22 and the outer member 20, 20b is then forced to its retracted position. When the feed mechanism is entirely collapsed, control handle 27 is returned to neutral position (a) (Figs. 7 and 8).

In the embodiment of the invention herein disclosed the power feed device, when collapsed, is only about 22 inches long but is capable of extending to more than twice that length, i. e., about inches. As arranged, its overall length is not greater but much less than the conventional uide shell and the entire feeding device is aiways within a vertical projection of the same. Moreover, the feed mechanism has only a slight lateral projectio-n (Fi 3) with the result that it does not increase either the bull; or the weight of the shell mounted drill outfit to any objectionable extent. Brackets 31 permit its convenient attachment to and detachment from the shell mount and provide a rigid or fixed connection to such a support. The use of resilient means or springs in the connection between the feeding device and the drill forms an equalizer for variations in center distances, cushions the feed piston against severe longitudinal or lateral shocks, and prevents binding of the feed mechanism. Through manual control valve 27 and feed screw handle 5 the operator is at all times in full control of the device and can combine manual operation with power operation or rely upon either exclusively as he wishes.

The arrangement of the pistons and cylinders, which constitute the fluid pressure feed, forms the subject of divisional application, Serial No. 661,212 filed March 17, 1933.

While the invention has been herein disclosed in a. preferred embodiment, it is to be understood that it is not limited to the specific details thereof but covers all changes,

curing the end parts thereof to the shell mount and to the drill respectively independently of said manual means.

2. The combination with a shell mount and a percussive drill slidably mounted thereon, V

screw for moving the drill thereon, of a fluid the mount having a manually actuated feed pressure power feed comprising a plurality oftelescoping parts, a bracket on one of said parts for removably securing the same to said mount, and clamping means on another of said parts to secure the same to said drill, said bracket and said means being independent of said feed screw connection to said drill and mount.

3. In combination, a shell mount, a percussive drill slidably supported thereon, said mount having manually operated means for controlling the position of said drill thereon including a feed screw, a power feed comprising telescoping parts secured to said mount at one side thereof and in parallelism with said drill, and a connecting member disposed transversely of said drill and feed, said member being rigidly connected to said drill and resiliently connected to one of the parts of said feed.

4. In combination, a shell mount, a per cussive drill slidably supported thereon, said mount having a manually operated feed screw for controlling the position of said drill on said mount, a power feed secured to said mount and comprising a plurality of telescoping parts, and means for securing said feed to said drill independently of said feed nut connection comprising a transversely extended arm having a clamp at one end secured to said drill and having its other end sleeved over one of the parts of said feed, and resilient means establishing a floating connection between said sleeved end of said arm and said last-named feed part.

5. In combination, a shell mount, a percussive drill slidably supported thereon, said mount having a manually operated feed screw for controlling the position of said drill on said mount, a power feed secured to said mount and comprising a plurality of telescoping parts, and means for securing said feed to said drill independently of said feed establishing a transversely floating connece tion between said sleeved end of said arm and said last-named feed part.

6. In combination, a shell mount'having guide grooves, a percussive tool supported for movement on said mount and comprising a cylinder having slides cooperating with said guide grooves, a bearing yoke supported by two parallel through bolts secured to said mount, a screw feed j ournalled in the bearing yoke and cooperating with the cylinder for feeding the latter, spacing sleeves surrounding said through bolts, a power feed for said tool ofi'set from the mount and comprising telescoping members, one of saidtelescoping members being attached to said percussive tool for feeding the same, and another of said telescoping members being supported upon the mount by means of two laterally extending brackets each having perforations for receiving the through bolts, one of said brackets being clamped between the spacing sleeves and the shell mount, and the other bracket being clamped between the spacing sleeves and the bearing yoke.

Signed by me at Detroit, in the county of Wayne and State of Michigan this 10th day of October, 1929.

GUSTAVE M. NELL. 

